Such a suspension thrust bearing device generally comprises a rolling bearing forming an axial thrust bearing and comprising an upper ring and a lower ring between which are arranged a plurality of rolling elements, for example balls or rollers. Preferably, use is made of an angular-contact rolling bearing which makes it possible to take up both the radial forces and the axial forces exerted on the device. The upper and lower rings are generally mounted in contact with lower and upper bearing or support parts, such as cups or caps. The upper and lower caps form a housing for the rings of the rolling bearing and provide the interface between the said rings and the surrounding elements.
Such a suspension thrust bearing device is arranged in the upper part of a suspension strut between the vehicle body shell and a suspension spring. The spring is generally installed around a shock absorber piston rod, the end of which is connected to the vehicle body shell via an elastic block which filters out vibrations. The suspension spring, generally a helical spring, bears axially, directly or indirectly, on the lower bearing cap of the suspension thrust bearing device. The upper bearing cap for its part is fixed with respect to the vehicle body shell.
Such a suspension thrust bearing device makes it possible to transmit axial forces between the suspension spring and the vehicle body shell while allowing a rotational movement between the lower bearing cap and the filtering elastic block resulting from a turning of the steered wheels of the vehicle and/or from the compression of the suspension spring.
Patent applications FR-A1-2 811 264 and WO-A1-2009/030842 describe such suspension thrust bearing devices comprising a lower support cap and a rolling bearing mounted to bear against the latter. The lower support cap is made of synthetic material and comprises a metal reinforcement or reinforcing insert improving the mechanical strength of the cap with respect to the forces exerted by the suspension spring.
The reinforcing insert must be sufficiently thick in order to ensure that the cap has sufficient stiffness. Now, since the insert is made of metal material, this increases the overall weight of the lower support cap, and more generally that of the thrust bearing device.
The present invention aims to overcome this disadvantage.